The First Night with the Duke

University student K is an ordinary young woman, but one day, she finds herself in her favorite romance novel set during historical times. She has now become the minor character Cha Seon Chaek. She is the daughter of a wealthy noble family, and her dream is to have a peaceful and normal life. Cha Seon Chaek, while possessed by K, then spends one night with Yi Beon, the lead male character in the novel. He comes from a royal lineage and is favored by the King. Yi Beon has a cold-blooded personality and is gifted with an attractive appearance and outstanding martial arts skills. He has also experienced a heartbreaking past. Somehow, Yi Beon and Cha Seon Chaek happen to meet and talk. Yi Beon is consoled by her about his heartbreaking past. They spend the night together. Soon, Cha Seon Chaek tries to connect Yi Beon to Cho Eun Ae, who is the lead female character in the novel. According to the novel, Yi Beon and Cho Eun Ae are supposed to fall in love, but due to the appearance of Cha Seon Chaek, Cho Eun Ae's fate has changed. No matter how hard Cha Seon Chaek tries, Yi Beon’s love always finds its way back to her. Other people around them include Jung Su Gyeom and Do Hwa Sun. Jung Su Gyeom is a young officer from a prestigious family. He is Yi Beon’s only friend. Do Hwa Sun is an ambitious woman whose life goal is to marry Yi Beon and become a member of the royal family.